On Thu, May 31, 2018 at 06:41:46PM -0500, Dave Chiluk wrote: > When moving xfs volumes between kernels that have 96f859d52 and don't > have 96f859d52, there is potential for a filesystem crash if the agfl > has wrapped (flfirst > fllast). Depending on which filesystem this is > this can take down the whole machine. > > Such is the case when upgrading from the stock Centos 7 3.13 to the > kernel.org stable kernels (via elrepo). Another possible common > boundary cross I noticed was early Ubuntu kernel v4.4 to recent v4.4. > We've been hitting this crash roughly once a week in our cloud, and it > has produced the below stack trace. > > The solution prefers to reset the agfl and leak a few blocks instead of > shutting down the filesystem. The leaked blocks can be recovered using > a xfs_repair. > > The attached patch is a backport of a27ba2607 due to a78ee256c. It is > intended for and tested on the v4.4 stream, but should apply to all > kernels that lack upstream a78ee256c. Thanks, now queued up. greg k-h
